Friction let-off for looms



Dec. 22, 1925- H. H. WATSON FRICTION LET-OFF FOR LOOMS 2 Sh eats-$11661: 1

Filed May 4, l'925 Deco H. H. WATSON FRICTION LET-OFF FOR LOOMS Filed May 4, 1925 2 Sheets-Sheet Patented Dec. 22, 1925.

UNITED STATES HERIBERT H. WATSON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CROMPTON & 0 F WORCESTER, MASSACHUSETTS, A CORPORATION OF KNOWLES Loon: worms,

MASSACHUSETTS.

PATENT OFFICE} FRICTION LET-OFF FOR LOOMS.

Application filed- May 4, 1925. Serial No. 27,719.

To all whom it may concern:

Be it known that I, HERBERT H. WATSON, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Friction Let-Off for Looms, of which the following is a specification.

This invention relates to improvements in let-off mechanism for looms and more particularly to a let-off having two friction elements one of which moves with the warp beam and the other of which is normally stationary to resist movement of the beam but is movable manually to reverse the warp beam, the reversing force being transmitted through the friction surfaces. In such devices it is desirable to adjust the friction from a convenient part of the loom, and it is accordingly the principal object of my invention to provide a convenient adjustment for this type of let-off.

Another object of' my invention is to provide an adjustable friction let-off which will permit a reversal of the warp beam without altering the adjustmentof the friction.

A further object of the invention is to provide a let-0E with an expansible friction element which may be varied in size by means of a double acting reciprocable pawl and ratchet mechanism.

A more particular object of the invention is to employ a toggle joint connection between the free ends of an expansible friction element which shall be variable by means of a cam face movable at the will ofthe weaver to alter the tension on the warp irrespective of the angular position of the friction element. l

With these and other objects in view which 'will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings wherein a convenient embodiment of my invention is illustrated,

Fig. 1 is aside elevation of a loom showingv myinvention applied thereto,

Fig. 2 is an enlarged vertical. section on line 2-2 of Fig.1, a

Fig. 3 is a diametral section through the friction device on line 33 of Fig. 4, Fig. 4-is a section taken on line 44 of Fig. 3 showing the parts placed to provide relatively low friction, V

I Fig. 5 is a view similar to Fig. 4 but showingthe parts in a different position to afford relatively high friction.

Fig. 6 is a detail front elevation .taken on line 66of Fig. 1, and showing the methodoflocki'ng the hand lever by means of which the double acting pawl is actuated,

Fig. 7; is an enlarged fragmentary View loodl-ring in the direction of arrow 7, Fig. 4, an

' Fig. 8 is a to plan view of the structure shown in Fig. a

Referring more particularly to Figs. 1 and. 2 it will be seen that I have provided a loom frame 10 having a lay 11 and a warp beam 12 mounted for rotation on the loom frame. Secured to each end of the warp beam is a gear 13 which meshes with a pinion 14. The warpI/V is led from the beam 12 around the whip roll 15, thence through harnesses not shown to the forward part of the loom. The matter thus far described is of common construction and forms no part of my invention.

, My invention relates more particularly to means for placing tension on the warp W in such a way as to permit, adjustment of the tension as well as reversal of the beam by acting on one of the friction elements. In carrying out my invention I provide a rearwardly extending shaft 20 having a hand wheel 21 thereon and mounted in bearings 22 secured to the loom frame. The rear end of said shaft 20 has secured thereto a worm 23 which'meshes with worm teeth 24 formed on one of two drums 24: which are secured to shaft 25 mounted for rotation on the loom frame 10. Each of said drums 24; has an interior friction surface 26 substantially concentric with the shaft 25 and adapted to have frictional contact with a fiexible arcuate band 27 the outer surface of which may be provided with leather or other friction material. Said surfaces 26 and bands 21 constitute the friction elements which resist rotation of the warp beam 12.v With the exception of the worm teeth 24 the drum and parts associated therewith are identical and a description of one will suffice for both The intermediate portionof band 27'h-as securedthereto a pair of guides 28 between which extends a pin 29 extending between the-forked end 30 of an arm 31 having a hub 32 loosely mounted on the shaft 25. Pinions 14 are secured to hubs 32 and rotate with the friction bands. The adjacent ends of band 27 are provided with other series.

bearings 33 and 34, respectively, to which are pivotally' connected'the outer ends of links 35 forming a toggle and pivoted together by means-of :pin 36.

Mounted for freeiotation on said pin 36 is airoller 37 which is-positioned forenga'gement with a -rotatable-;pressure member -38 having a series of notches 39 in the outer face thereof of different distances from "the axis of the shaft. 25. Eiaid pressure imember has integral therewith a hub 40 which-4s freely rotatableon hub 32 and has; formed therewithtwo series of ratchet teeth 41 and -42, respectively,theteeth of one series-pointing in a direction opposite to the-teeth ofthe Said series of 'te'ethare spaced to provide aru-n :43 th'erebetw'een which'receives a lug 44 depending from a pawl 45 formed'on therear'end of the rod-45?; -S'aid pawl 45 has a pull detent 4 6 to engage the teeth 41 and a push detent 4'7 'to aen'ga'ge the teeth '42." Said detents are laterally offset so that each cooperates with'bu t one series of teeth and said detents are spaced sufficiently farapart longitudinally so that when the parts are in the position shown in Fig. '4, said 'detents 46 and 47 are-out of the path of the teeth of the series 41 :and 42 and do not interfere with free rotation of:thc hub 40.

In order'to actuate the pawls 45therods 45 are each connected to anarm '48 which 7 is secured to shaft 49 extending-across the loom. Fastened to said shaft 49 is a third arm 50 which is'connected by-mean-sof link 51 to arm 52 of th'elever53-pivoted as at 54 to a fixed parto-fthe loom. Lever 53 extends, forwardly to provide a convenient hand hold for the operator and is normally received in a notch 55defined between apair of lugs 56 formed on a plate 57 bolted or otherwise secured to the-frame 10 of the loom. When thelever 53 is in the position shown in Figs. land 6 the pawl '45 will be as shown in Fig. 4:so as to permit uninterrupted rotation of the hub 40.

During the normal operation of the loom the worm =23 prevents rotation of wormteeth 24tholding the drums 24 in fixed position. As the warp beam :12 rotates .in a counterclockwise direction as shown in Fig. 1 to supply yarn the :gears 13 will move therewith and cause pinio'ns 1 4 to have a right hand rotation as vi'ewediin Fig. '1. Inasmuch as said pinions are fastened to the hub 32 as shown in Fig. 3 the friction members 27 will be required to move also and the warp will be resisted in its movement by the friction existing between said members 27 and the interior friction surfaces 26 of the friction drums 24 The pressure members 13.8 are ."olfset fromythe paw-ls 45 and move with the fIlLCtl'OIL-JbZIHdS and the devices associated therewithas a unit about the shaft 25.

When it is :desired to vary the pressure between the friction bands 27' and the sur- "faces 26 thelever 5 3 will be flexed inwardly and removed from the'notch 55 and then raised or lowered to "the*dctted*1ine position shown in Fig. 1 "depending upon whether the :friction is to *be tightened or released. The lever '53 will bevigbra'te'd until roll 37 occupies the notch '39 "which provi'des the proper friction, at *which f't-ime said lever 53 will be restored "to its' normal position shown in fullline's in' Figs. 1"andr'6. The bands "27 are sulficiently strong-to withstand the lateral thrust of the "toggles without buckling and the recesses 39 ai'e'of sufli'cient depth to prevent accidental displacement of the rolls "37. Fig. shows the position the toggle "and fttictioh member BS'a-ssum'e when the pressure hasbee'n increased, the pawl 45 being drawn to the right to producea corresponding 'motion of the 'pressure device. It would'be "necessary-to restore the pawlto its imid-pos-ition before weaving could'be resumed. I

From the foregoing it will be "seen that Iha've provided a *let-foff mechanism having a {pair of friction elements one of which moves with the "beam and the other of whichcan be nriovednrz'tnu'alily to effectieverse rotation of the/beam and I tha't' the pressure between said elements can be varied conveniently *by means operable from the front 'o'f tlaie loorn irrespective time angular position of the friction elements. It will further -be' seen that the pawl is so constructed-that the teeth thereof are =out of the pathof the-ratchts when inn'ormal position so 'as' 'to:permitnninterrupted rotation *of the beam and it will furtherbenoted that the toggle is held" against ,"acciden-tal imsetting by the po'ckets 39. I

Having thus described any -inventi'on it will 'be apparent that- 'clran ges a d modifications may be madetherein by; those skilled inthe art with-'eutdeparti ng f'ro'm the spit-it and scope 'of -the invention, and I do not Wi sh to be limited to the details herein disclosed, but what I clainris;

1. 1 11 a friction 'let o fi ferlooms, a warp beam, a friction element movable; therewi-th, a normally stationairy friction element coacting withthe first element to resist forward rnovement'of the .w arp :btith'lll, me ans' to move the second element tofreverse the move ment of the warp beam, and means to adjust the pressure between said elements irrespective of the relative angular positions of said elements.

2. In a friction let-off for looms, a warp beam, a friction element movable therewith, a normally stationary friction element coacting with the first element to resist forward movement of the warp beam, means to move the second element to reverse the movement of the warp beam, and means to adjust the 1 pressure between said elements independently of the angular position of said second element.

3. In a friction let-ofi" for looms, a warp beam, a friction element movable therewith,

a normally stationary friction element tocoact with the first element to resist forward movement of the warp beam, said normally stationary element being movable from one position to another, means to vary the frictional pressure between the elements in any angular position thereof, and means to move said normally stationary element to effect a reverse movement of thewarp beam, said friction elements retaining their 1 relative adjustment during the reverse movement of the beam.

4e. In a friction let-off for looms, a warp beam, a friction element movable with the warp beam, a normally stationary friction element coacting with the first named element to resist forward movement of the warp beam, manual means for varying the position of the normally stationary element to reverse the warp beam, means movable with the first named element to vary the pressure between said elements, and manual means for controlling said adjusting means.

5. In a friction let-off for looms, a warp beam, a friction element movable therewith, a second normally stationary friction element coacting with the first named element to resist forward movement of the beam, means to vary the pressure of the including an inclined surface movable about the axis of the first named element, and

means to move said inclined surface independently of the angular positions of the elements.

7. In a friction let-off for looms, a warp beam, a friction element movable therewith, a normally stationary friction element coacting with the first named element to resist forward movement of the beam and movable to effect reverse movement of the beam, means to vary the frictional pressure between said elements, said means includin a toggle and an inclined surface 'mova 1e about the axis of one of said elements, and manually controlled means to move said inclined surface in either direction independently of the angular positions of the elements to vary the frictional pressure between said elements.

8. In a friction let-off for looms, a warp beam, a friction element movable therewith, a normally stationary friction element coacting with the first named element to resist forward movement of the beam and movable to effecta reverse movement ofthe beam, means to vary the frictional pressure between said elements, said means including a toggle and a rotatable member having an inclined surface to coact with the toggle, two series of ratchet teeth formed on said rotatablemember, one series pointing in one direction and the other series pointing in the opposite direction, and a double acting manually controllable pawl having oppositely disposed detents to cooperate with the teeth to move said member in either direction.

9. In a friction let-off for looms, a warp beam, a friction element movable therewith, a normally stationary friction element coacting with the first named element to resist forward movement of the beam and movable to effect a reverse movement of the beam, means to vary the frictional pressure between said elements, said means including a toggle and a rotatable member having an inclined surface to coact with the toggle, two series of ratchet teeth formed on said rotatable member, one series pointing in one direction and the other series pointing in the opposite direction, and a double acting manually controllable pawl having oppositely disposed detents to cooperate with the teeth to move said member in either direction, said detents being out of contact with the teeth'when said letoff is in operative position.

In testimony whereof I have hereunto affixed my signature. 

